Is weight really mater?

If both amps are rated at 100wpc, in general, would one weight 100 lbs sounds fuller, more textures and juice, and is a “better” amp than the one weights only at 8 lbs? (Nope, I’m not comparing commercial PAs or Karaoke mixer systems.)
Mark Levinson No. 331 is weighted around 100 lbs while the amazing Jeff Rowland Model 102 is weighted shockingly at 7.4 lbs. Yup, you read right, “seven point four pounds”.
Can I use this factor for my determination?
In real life, bigger men will tend to lift bigger weights than tinny men, but how about electronic amplifications? Shouldn’t they too need bigger toroid transformer, bigger caps, bigger heat sinks, etc? What’s with the 8 lbs?
Please simplify much possible your comments so others (and I) would understand.
Speakers are smalll 6-ohm floorstanding Sonus Faber Grand Piano Home series. Thanks all.